Fuel crushing and feeding device for furnaces



(No Model.) 2 Sheets-Sheet 1.

' N. W. PRATT. V EUEL GRUSH'ING AND FEEDING DEVICE FOR FURNAGES.

No. 443,109. Patented Dec. 23, 1890.

WITNESSES: INVENTOR' ATTORNEY (No Model.) 2 Sheets-Sheet 2.

N. W. PRATT.. FUEL GRUSHING AND FEEDING DEVIGE FOR FURNACES.

No. 443,109. Patented Dec. 28, 1890.

W|TNES$ES1 INVENTUB 6?? MW. [1 1 %d v: d BY UNITED STATES PATENT OFFICE.

NAT. \V. PRATT, OF BROOKLYN, NElV YORK.

FUEL CRUSHING AND FEEDING DEVICE FOR FURNACES.

SPECIFICATION forming part of Letters Patent No. 443,109, dated December 23, 1890.

Application filed December 23, 1889- Serial No. 334,726. (No model.)

To all whom it may concern:

Be it known that I, NAT. W. PRATT, a citizen of the United States, residing at Brooklyn, in the county of Kings and State of New York, have invented certain new and useful Improvements in Fuel Crushing and Feeding Devices for Furnaces, of which the following is a specification.

My invention is applicable to rotary grates wherein it is essential to apportion the coal or other fuel in variable quantities upon the different circumferences of the grate-surface.

My invention consists of a combined crusher and feeder rotative upon an axis located in a vertical plane coincident with a radius of the rotary-grate, the spiral blades of the crusher being inclined with reference to the direction of its rotation, whereby to apportion the fuel chiefly toward the outer circumference of the grate-surface.

Referring to the drawings, Figure 1 is a longitudinal sectional elevation of a furnace having a rotary grate and to which the application of the crusher and feeder is illustrated. Fig. 2 is a front elevation of Fig. 1, and Fig. 3 is an enlarged vertical cross-section showing a portion of thehopper and the crusher therein.

The revolving grate is composed of sections which are designated by l 1, Fig. 1, and the revolving frame supporting the bars or sections is designated by 2 2, such frame rotating upon wheels 3 upon a circular track 4.

5 is a central pier, between which and the circular walls 6 a pathway is formed for the fuel.

7 is a dome or crown of the furnace, and 8 an opening therein through which the fire is sues to the space to be heated, such as that beneath a tubular boiler 9.

10 is an opening through which the fuel is supplied, the combustion taking place at one side of the orbit of the grate beneath the opening 8.

11 indicates a portion of a radial bridge, (the same being broken away,) which separates the incoming fuel from the consumed part thereof that has completed the circuit, the ashes being discharged as described in my patent application filed March 5, 1889,No. 301,950. The outer circumference of the grate requires to be supplied with the major portion of the fuel, owing to its excess of surface, and also, for the purpose of sealing the space between the upturned flange 12 of the grate and the adjacentwall 6, it becomes important to bank the coal chiefly toward the outer portion of the grate. To accomplish this the present invention is especially adapted, and it consists as follows:

39 is a hopper in which the coal is supplied, and 41 the crushing and feeding device, having its axis of rotation located in a vertical plane coincident with a radius of the circular grate 1.

45 is the cylindrical case partly enveloping the crusher and feeder and forming the neck of the hopper. The blades 41 of the crusher and feeder form pockets 60, which are filled from the hopper by gravitation of the fuel into them as the blades rotate in the direction indicated by arrows. Such lumps of coal as may be larger than the intended size are caught between the edges of the blades 4-1 and the adjacent rigid edges of the casing and broken, being measured out in given quantities at every revolution and showered through the opening 10 in the brick-work down upon the grate. The sides of the cylindric case 45 inclose the pockets 60, as shown in Fig. 3, while the same pass through an intermediate position between the upper opening at the throat of the hopper and the lower opening 10, thereby excluding undue drafts of air above the grate. Owing to the helical form of the crusher, the work is equalized at every point of rotation and the fuel is fed continuously and evenly distributed at each given circumference of the grate. As inclicated in Fig. 1, the spiral inclination of the blades and their direction of rotation with reference to such inclination tends to move the bulk of the fuel outwardly from the portion of the crusher above the smaller circumference of the grate to that above the larger. The opening 10 is also diverged in increasing breadth toward its outer portion, as indicated in Fig. 2, providing for the passage of the bulk of the fuel so disposed.

The speed of the feeder ll is made variable with reference to the speed of the grate to suit the requirements of the fire. To this purpose suitable automatic actuating devices are employed for each, such as indicated in the drawings and as described in the aforesaid patent application. The crusher and feeder is revolved by the Worm-gear 42 keyed to its shaft, and the Worm $3 upon the counter-shaft engages with it, said counter-shaft bearing also a ratchet-wheel ii, that is operated by the pawl 46 on the lever 48, connected at adjustable distances from its fulcrum with the reciprocating operating-rod 47, which receives its motion from an eccentric or other suitable device.

Having thus fully described my invention, What Iclaim, and desire to secure by Letters Patent, is-

NAT. W. PRATT.

Witnesses:

PARKER, (I-ms. IIANIMANN. 

